Fluid-pressure-operated tool.



f PATENTBD JULm, 1907.

0.- H; JOHNSON.

FLUID BRESSURBOPERATBD TooL. APPLICATION FILED JULY Z1, 1902. BENEWID AUG. 4, 1906.

s SHEETS-SHEET 1;

N 'we/Zal PATENT@ JULY z, 1901 z. Bmmwnn AUG. 4, 19in.

' aslnnzrs-smmr`a- 10.858,398. l V c. H. JOHNSON.

FLUID BBssURE-OPERATED Toor.. ArrLIqATIoN FILED JULY 21, 19o

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llllll IU "um mmm 19.858,398. PATUNTUD JULY 21907. l G. H. JOHNSON.

FLUID PRESSURE UPURATBU TOUL. l. APPLICATION FILED JULY 21, 1902; RENWED AUG. 4, 19.06.v

' 3 SHEETS-SHEET a.

NrrED STATES PATMENT omnes.

CHARLES H. JOHNSON,

or oAN'roN, omo, AssreNoRQnY MEsNE AssIeNMEN'rs-'ro THE PITTSBURG PNEUMATIC COMIANY, OF CANTON, OHIO, A CORPORATION OF N'EW JERSEY.

To all whom it may concern:

. Be it known that I, CHARLES H. JOHNSON, a citizen of the United States, residing at Canton, county of Stark, State ofOhio, have invented a certain new and useful Improvement in Fluid-PressurAeOperatedTools;

ated rtools, and more particularly to valve mechanism controlling the admissionand exhaustof fluid pressure to the cylinder. j K In fluidA pressure tools it isdesirable that the valve co trolling the supply' and exhaust ofl pressure tothe en s of the cylinder should be operated to cut off the supply from the respective sides of the piston before it reaches the end of its stroke, and it is also desirable that the valve should be quickly shifted from oneposition to theother, and when shifted, positively held by a preponderance of pressure in each position' until the piston reaches the predetermined pointin its stroke, when the supply and exhaust of fluid pressure to the respective `ends of the cylinder should be reversed.v Fluid pressure operated tools of the character retv ferred to are of such power that if the throttle valve* is open when the snap or die is out of contact with the object being worked upon,vthe snap will be violently ejected Afrom the cylinder and thrown a considerable distance owing to the impact ofthe piston therewith.

pressure to the respective ends of the cylinder are controlled by a piston valve, the reciprocation of which to its controlling positions will be quickly and certainly It is therefore desirable that the reciprocation ofthe piston should be automatically preventedwhen the snap is not in contact with an object. v

An object of my invention is to provide a fluid pressure operated tool in which the supply andA exhaust of accomplished and which when shifted will bermly held in each position-until again shifted by the piston reaching' the proper predetermined point in its throw.

A further object of my invention is to construct a fluid pressure operated tool of the character referred to in which the working end ol the cylinder will be auto matically connected with the atmospherewhen the snap isnot incontact with an object, thereby preventing the reciprocation of the piston toward the snap.

A still further object'of my invention is to. provide a fluid pressure operated tool of the type referred to which will be comparatively simple in construction and ellicient in operation. A

My invention generally stated consists in a cylinder within which a piston is reciprocated by the supply and Specification of Letters Patent.

, FLUID-PRESSURE-OPERTED TOOL.

l Patented July 2, 1907.

Application filed July`21, 1902. Renew-reni August 4, 1906. Serial No. 329,215,

exhaust of pressure to its opposite sides, the supply and exhaust of pressure beingcontrolled by a differential piston valve having radial surfaces one of which is constantly exposed to pressure tending to throw the valve to and retain it in position to admit fluid pressure to the vback or working' end of the cylinder, the throw of the valve in either directionbeing effected by the-admission and exhaust of fluid pressure to and fromv ythe exterior areas of the opposite ends of the valve.

. My invention further. consists in a fluid pressure operated tool in which a sleeve surrounds the back end of the cylinder and is automatically moved relatively thereto by fluid-pressure whenever the snap is disengaged .from an object, thereby bringing an exhaust port into register with the port in the front end of the cylinder so that the pressure which impels the piston into contact with the snap is relieved.

The invention will -be more fully'descr'ibed hereinafter with reference to the accompanying drawings, in

ient and'practical form, and in which-'- Figure l" is a longitudinal vertical section of my invention taken on line 1`-1, Fig. 2", the parts being shown in' the positions they assume'when the snapvis in Contact with an obj ect Fig. 2 a horizontal sectional view of my invention taken on line 2-`-2, Fig. 1, looking in the di rection'of the arrows, the parts being in the positions they assume when the snap is disengaged fromfan object;`Fig 3 a detail sectional view through the valve casing; Fig. 1an enlarged cross section view on line 3-3, Fig. l, the valve being removed; Fig. 5 a sectional view 'which the same is illustratedas embodied in a conven of the valve casing and showing the valve in elevation in the position which it assumes when pressure is being 'admitted to theu'iback or working end of the cylinder;

Fig. 6 a view siinilar to Fig; 5, the valve being shown in the position in ilhich pressure is admitted to the front end of the cylinder in which 'the tool is located; Fig. 7 an elevational view ofthe piston valve; Fig. 8 a longitudinal section of the valve; Fig. '9 a view similar to Fig. l i

` showing a modification; Figl. 10 a view similar' to Fig. 4

of the modification shown in Fig. 9; and Fig. ll a View similar to Fig. 8 showing the valve used in the modifications illustrated in Figs. 9 and l0.

The saine reference characters are used to indicate the same parts in the several figures of the drawings.

Reference letter A indicates the handle of the tool which is provided with a tubular extension A which loo surrounds the back end of the cylinder C. A lever .A$17

` is pivotally supprted'in the handle A and is provided with a. lug a4 adapted, to engage the end of a valve stern f b4, the latter being connected to a throttle valve B4. A

being supported upon a plug l2 screwed withina socket 10 5 .spring B3 retains the T'throttle valve against its 'seat y' formed in the handle A, the opposite end of such spring` formed'in thehandle'in alinenlent with the valve'seat'. A passage B, which may be screw threaded, is formed in i the handle A and is adapted to be connected with a cony, between which and the outer are lfor'r'nedy passages c2, c4 `pressure ows to andfrom y a ferule G. Av snap or die H` is supportedwithin the -ierrule G and is retained therein; by any suitable means such for'instauce asethe spring ring gwhich is seated within anannular groove formed in the interior surface oft e ierruleA near the outer end thereof.. lA piston K is located within the cylinder and is-recipr cated therein by 'the admission and exhaust of fluid pressure toA the opposite'ends thereof;

'lhe end. of the cylinder opposite to the die is located within the tubular extension A to which it is secured by means 0i a flat key the outer ends of said key extending through elongated slots (a7- formed-through the `tubular' extension of the handle so as to'permit a relaf' tive movement between the handle and the cylinder.. A' cylinder head C closes thev end or the cylinder within the .handle by means of ,a'screw threaded engagement 'lio y the passages c2, c3, c,

therewith. 'The 'cylinder head is provided with. a

chamber c into which a cylinder A3 forrned integrally with the-handle'isadapted to lextend." A piston or plunger fits within the cylinder A3 and rests against the cylinder head C7..y A passage a isformed in the handle A extending to the-end of the cylinder Aa from ay vpoint below'the throttle valve B4. A port a2 extends through the sleeve c" around the cylinder and is closed by the Vtubular extension A o f thehandle when the tool is forced against the object being 'worked'upon but is uncovered when the handle and cylinder move relafl tively apartto the position shown in Fig. 2 when the tool is not in Contact with'an object.'

A transverse cylindrical valve casing A2 is formedA in,

the valve handle beneath the tubular extension A and preferably integrally therewith. The valve casing A2 is provided with a series of annular passage ways a2, a3, a, and T15, adapted to communicate with passages c2, c2, c4, and c5 which extend through the sleeve c' and which communicate with the interior of the cylinder. The valve casing A2 is also provided with a passagea which communicates with a chamber A6 located above the seat for the throttle valve and through which pressure is admitted when thethrottle valve is open. An annular passage a is formed in the valve casing A2 and cornmunicates with an atmospheric exhaust port.

' The ports through the-sleeve c in which terminate and c5, register with the passages a2, a3, a4, and a5, in the Valve casing when the handle A is in the position indicated in Fig. 1 of the-drawing.

The passage or passages c3 lead directly to the interior of.

the working end of the cylinder, while the passage c* leads to the end of the cylinder adjacent to the tool', such passages c2 and t4 affording communication between the supply of fluid pressure and thc opposite ends ofthe piston. The passage c leads to the interior of the cylinder at a point distant from its front end slightly greater than the length of the piston, while the passage c2 communicates with the interior of the cylinder at a controlling the series of y enlarged ends D. within the chambers E and E2 respectively of thebush- 'is provided with a central passage-way communicates radial passages d extending through thc,

point located aidistance from the piston head C slightly greater than thelen'gth of the piston.

A bushing E is located within lthe valve casing A2 within'which the piston valve reciprocates.' Series oi passages e, e, e2, 3, e, and e5 extend through ,the bushing-E and `register with the i l a5 respectively formed in the valve casing A2.y Chainbers E1 and E2are formed in. the oppositeends oi the bushing, such chambers being separated by a central annular partition. The bore through the centralv partition is reduced between the chamber E2, thereby forminglanyannular shoulder e. A passage e2 is formed in the central partition and connects one of the series of ports e3 with the chamber E2. Caps F," and F2 are screwed into the-respective ends of the valvecasing A2 and engage the opposite ends of the bushing. E.

Thepiston valve located within the bushing and ports therethrough comprises and D2 of the same diameter fitting series bf ports lev and the ing. The portion4 D2 of the valve is separate froml the -v rest of the valve and constitutes a piston independently movable within the chamber E2. The reduced portion of the valve intermediate of the enlarged ends enlarged end D/andiadial passages d3 located adjacent` to an annular shoulder D3. The end of the passage d adjacent to the independent piston D2 is closed by a 'screw ythreaded plug dit'. The annular shoulder D3 is of a diameter to closely engage the larger bore. through the central partition in the bushing `E, whilethc portion of the valve betweensuch shoulder and the inde- -pendent piston D2 is of a diameter to t within the refduced' bore of the central partition f the bushing ad'- jacent to the fchamber E2. l A, 4 The operation of the embodiment of my invention illustrated in Figs. 1 to 8 is as follows; When the snap or die in the end of the tool is out of contact with an object the fluid pressure which to the cylinder A3 is exerted upon the end of the plunger k andthereby moves the handle and cylinder apart as indicated in Fig. 2. The exhaust port as is consequently uncovered by the tubular projection A/ and `permits the fluid pressure to flow directly to the. utmosphere from the working end of the cylinder, tlwrcby preventing the reciprocation of the piston although the throttle valve may be open. When the tool is to be used and the snap thereof is forced againstthc object, the handle slides upon the front end of the c'ylindcr tho distance permitted by the elongated slots .a7 through which the key c extends, such movement of the handle being effected by sufficient force applied thereto to overcome the pressure of the fluid exerted between the plunger lc and the adjacent wall of the handle. The exhaust d I'with which passes through the passage d llO port aB is consequently covered by the tubular extonl sion A/ of the handle, thereby discontinuing the communication between the Working und of the cylinder and the. atmosphere. The lever A4 when oscillatod unseats the throttle valve B4 and permits the fluid prossure. to flow from the source thereof through the opening B into thc chamber A5 in the handle, and thence through the port c formed near the center of the valve casing A2. i lf the valve is in the position shown in Fig. 5, the prcssure will flow through the ports e in the bushing, thence around the reduced portion o the valve through the ports e3 and annular port a3, thence throughpassages c3 into theback end oi the cylinder. The piston K will be reciprocated in the cylinder,towards the snap or dieY H which receives the necessaryimpact to perform the ,work desired. When the piston uncovers the port c5 the pressure passes therethrough to the passage a.5 in the valve casing, thence through the ports e5 in the end of the bushing and is exerted upon the exterior area of the ,enlarged portion Dhof the valve. The valve is consequently moved irom the positionindicated in Fig. 5 to that indicated in Fig. 6 by reason of the exterior area oi the end of the enlarged portion D being greater than connects the back end of the cylinder with the atmosphere through the following ports and passages; c3, a3,

e3, `e,.and exhaust port a while fluidpressure is ad- "mitted to the end of the cylinder adjacent to the die through the lfollowing ports and passages, a, e, d3, d, d@

l e4, af, and c4. The valve is retained in the position indi- .cated in Fig. 6 by reason of the pressure admitted from the cylinder through the passage c5, etc. being retained in the-chamber E by the blanking of the port c5 by the piston at the commencement of its return stroke towards the handle of the tool-and subsequently by the uncovering oi the port c5 by the piston and the consequent communication with the motive fiuid which impels the piston away irornithe tool. It will be noticed that the valve in the position shown in Fig. 6 is subjected to pressure on the annular shoulder D3 but as such area is lfar less than that of the exterior surface oi the enlarged portion Dev the valve is retained in the position indicated in view of the fact that both surfaces oi the independent piston D2 are connected with the exhaust, one surface through the passages 0,2, c2, to the back end of v the cylinder and thence to the exhaust, and the other surface through the passage e7 to the passagel e3 and thence through the exhaust port a. The area of the l end Dfis also exposed to the exhaust through the cham ber E2 and passage e". When the piston in its movement towards thehandle uncovers the port c2 pressure flows therethrough thence'through the passages c2 and a2 to the exterior surface o the independent piston D2 which being of the same area as the exterior surface oi the enlarged end D moves the piston from the position indicated i'n Fig. 6 to that indicated in Fig.' 5 owing to the annular shoulder D3 being constantly exposed to A pressurev from the'supply. The movement oi the piston to the position shown in Fig. 5 connects the back end of the cylinder with the'supply oi motive fluid as above described and simultaneously connects the end of the cylinder adjacent to the tool with the exhaust through the following ports and passages; c4, a4, e4, e andvexhaust port a/. It will be noticed that when the valve is ,l first thrown to the position indicate/din Fig. l5 the port c will -be co1,1 .,1.ie'eted throughlthe cylinder with thel port and passage "cfwhich, as abovedescribed, is in communication with the exhaust, and in order to prevent the valve being immediatelyl reversed from the position shown in Fig. 5 to that shown in Fig. 6, the enlarged end D2 is formed separate from the rest of the valve and consequently it alone is moved within the chamber E2 while th rest of the valve is retained in the position shown in Fig. 5 by reason of pressureexerted upon the shoulder D3 of the valve as well as upon the end surface D5 owing to the flow ol pressure through the passage e7 and into the adjacent end of the chamber E2, the exterior end of the enlarged portion D being connected with the exhaust through the passages a5 and c5 andcylinder, the

`valve will be held immovably in the desired position.

In Figs. 9', 10 and 11 I have illustrated a slight modification of my invention, such modifiecation consisting in substituting for the independent pistonD2 and the plug d5 an integral part D6v the screw threaded reduced `portion d of which is screwed into the passage in the rest oi the valve, thereby uniting the two portions of the valve immovably together. An additional port c3 is formed through the cylinder adjacent to the cylin-.

der head C which communicates with the passage c2 at a point adjacent to the passage a2. The operation of this modification oi -my invention is the same in all respects as that 'above described in connection with the construction shown in Figs. I to 8 except that when the piston in moving toward the handle has uncovered the port c2 and consequently has placed the exterior area oi the enlarged end D Ain communication with the ex# haust through the exhausting end of the cylinder, the valve is prevented from at once reversing from the position shown in Fig. 10 by reason of fluid pressure passing through the port cG to the end of the chamber E2 and thereby compensating for any exhaust which oc-V curs through the port c2.

From the foregoing description it will be observed that I have .invented an improved valve mechanism for iuid pressure operated tools in which a piston valve is employed having an annular radial surface constantly exposed to fluid pressure, while the throttle valve is open, such constant pressure tending to move the valve to and retain the same in position .to connect the working end of the cylinder with the motive fluid. It will be further observed that I have provided fluid pressure actuated means always tending to relatively move the handle and cylinder so as to connect the back end oi the cylinder with an exhaust port, thereby obviatiug the danger of the die or snap beingejected from the cylinder when it is out ci contact with the object being worked upon. 4

While I have described more orlessfprecisely the details vof construction I do not wish to be understood as limiting-myself thereto, as I contemplate changes in form, .the proportion of parts, and the substitution of equivalents, as circumstances may suggest or render expedient, without departing from the spirit of my invention. i

lHaving now fully described my invention what I claim as new, and desire to secure by Letters Patent,

'1. In a -tluidpressurezoperated tool, the combination with a cylinder, of a piston adapted to reciprocate therein,

a valve casing having ports communicating' with said cyl'- inder, a piston valve vlocated in said casing controlling the. supply` and exhaust of fluid pressure and having two op, positely disposed radial surfaces one constantly exposed to fluid under.4 pressure retain itin position to admit fluid pressure to one end of the cylinder and the other constantly exposed to ythe atmosphereysaid valve 'havlngexterior end surfaces of greater. area than said radial surface alternately e'xposed to iluidpressure and to the atmosphere to reciprocate the f valve.

2.. in a4 fluid pressure' operated tool, they, combination with a cylinder, of a piston adapted to reciprocate therein,

ya valve casing havingports coin'municating'with said cylinder, a piston valve located in said casing controlling the y supply and exhaust of fluid pressure, and\ having two op` Vwitha cylinder,` of a piston 4adapted to reciprocate therein,` '2`5 casingv and controlled by the piston to admit and exhaust' fluid pressure through the cylinder to reciprocate the. valve.'v

3. In: a lluid pressure operated tool,y the combination a valve casing' having ports communicating with said cylluder, n plstonrvalve located in said casing controlling the supply'and exhaust of fluid'pre'ssure and having two I'oppositeiy" disposed radial surfaces .one constantlycx- Vpiston tothe opposite'ends oi. the yaive casing and 'conf posed to fluid under' pressure tending to'throw the valve to andretan it in position to admit Iiud pressure to one end of the cylinder and the other constantly exposed tov theatmosphere, said valve having exterior end surfaces ot' vgreater area than said radial surface, said c'ylinder having passages leading from points therein spaced from its ends a distance slightly greater than the length of the trolied by the piston vto admit and exhaust i'luid pressure to and from the valve casing to reciprocate the valve.

4. in a fluid pressure operated tool, the combination with a cylinder, ot a piston reciprocating therein, a valve casing having .ports communicating,r with the opposite ends of the cylinder, a differential piston valve in said 'casing having enlarged end portions and a restricted intermediate Portion around which fluid pressure flows to -one end'oi-fthe cylinder and through a passage in which fluid pressure passes to the other end of the cylinder', said cylinder having ports controlled by the piston leading to the opposite ends of the vulve casing fonadmitting thcrcto and exhausting therefrom fluid pressure through theori- -inderrio reciprocate the vulve.

5. In a fluid pressure operated tool, the. combination with a cylinder'r of u piston reciprocating therein, a valve -casing having ports communicating with the opposile lends of the cylinder', a differential piston valve havin; a

reduced intermediate portion around which liluid pressure flows to Ioneend of the cylinder 'and a passage therein through which tildpressure passes to the otherend of the cylinder.

6l `In a duid pressure operated tool,v the combination with a. cylinder/of a piston reciprocating therein, u valve casing having ports communicating with the opposite f ends of the cylinder', a differential piston valve in said casing having -enlarged end portions anda restricted intermediate portion around which fluid pressure iiowsto on'e end of acyiinder and through a central 'passage in 4which iiuid pressure flows t0 the other end of the cylinder', said cylinder having ports controlled by the piston leuding to the opposite ends of the valve casing for admitting thereon and exhausting therefrom fluid pressure through the cylinder 'voreciprocate the vulve.

7. in a'i'l/uill pressure operated iooltlre combination with a cylinder, of a piston adapted'to reciprocate therein, uvalve casing havingr ports communicating with the opposite ends of' said cylinder, a piston valve located in said. casing controlling,r the supply and exhaust ot iiuid pressureund having a radial surface constantly cxposcd to tiuld pressure tendingv to move tiie vaivc and rciair'r'it in position to admit iiuid pressure to the front chil of the cylinder, said vaiveeomprising enlarged end portions and :1 restricted intermediate portion around which'iiuid pressure flows to theback end of the cylinder' and through a central passage t'en'dingtothrow the vaive'to and bore. said reduced bore having ports leading from the slip- 4ply and to the bac-k end of 4the cylinder und one ot said- 'chambers having an exhaust port' and ports leading to the front end of the cylinder, a piston valve having enlarged in which fluid pressure iiows to the front end ofthe cyilnder, said'cylinder having ports controliedby the piston communicating with theopposite ends of the valve casing for admitting thereto and exhausting therefrom fluid tressure through-A t'he cylinder' to reciprocate the valve.l

8. In a fluid pressure operated tool, the combination with a cylinder,'of a piston reciprocating therein, a valve casing comprising end chambers separated by a reduced end portions located in said chambers of the valve casing and an intermediate portion extending through said reduced bore, and means for reciprocating the valve.

i). In a iiuid pressure operated tool, the combination with `n cylinder, of a piston reciprocating therein, a valve casing comprising end chambers separated by a reduced bore, said reduced bore having por'ts leading from the sup- 10() ply and to the back end of the cylinder' and one of said 'chambers having an exhaust port and ports leading to the frontend of the cylinder', a piston valve having enlarged end portions located in said chambers of the valve casing and an intermediate portion extending through said reduced bore, said cylinder' having passages leading from pointsthcreiri spaced from its opposite ends n distance slightly greater'lrthan the length ot the piston to the ends of said chambers and controlled by the piston to admit und exhaust'iiuid pressure alternately to and from the cham- 11() bers of the valve casing to reciprocate thc valve.

10. lu a fluid /pressure operated tool, the combination with a cylinder', of a piston.reciprocating therein, n valve casingcoinprislng end chambers separatori by u reduced bore, said reduced bore having ports leading from the supply and to the buck end of the cylinderuaud one of uuid t Achambers having exhaust ports and ports lending to the front end otthe cylinder, :r piston valve having,r enlarged end portions located in said chambers of the vulve casing and a hollow intermediate portion extending through said reduced bore around which iiuld pressure passes to the back cud of the cylinder; und through which iluld pres sure passes to thc front cud of the cylinder.

'11. in aiiuld pressure operated tool. the combination with a cylinder', of a reciprocating piston therein. u valve .125 casing having chambers separated by a reduced bore. said reduced bore `having ports icudingirom thc supply und to the buck end ot tho cylinder :rnd n passage connecting said latier port with oneof said chambers, thc other' of Huid chambers having,r exhaust ports uml ports loading: io the liront rnd ut' thc cylinder, :r piston valve havin;r rulurgcd rmi portions within said chambers :rmi a reduced interincdlaic portion within said reduced borc` oi' the casing said cylinder having.r ports controlled by the piston icadim;

ion. id chambers ot' thc valvt` casinar for alternating 1nd- 135 miiiirn;l thereto und exhausting,r ihcrciroin iiuid pressure through thc cylinder io reciprocate thc valve.

1:2. in a iiuid pressureI operated tool, tho combimition with u cylinder, o1" a riwprru'atlng piston therein, a vulvecasing; having; chambers separated b v :r reduced bore, Suid reduced bor huvinpr ports lcudiin,r from the supply und to the buck cnd oi the cylinder and a passage' connecting said latter port with one of' said chambers, the other oi' said chambers having exhaust poi-is und ports lending to the front cud'ot' the cylinder, :r piston vulve having enlarged 145 end portions within said cimmhcrs und :i reduccd intermediuic portion around which iluid prcssurc passes to the baci: end of the cylinder' und through which iiuid pressure passes Vio thc iront cmi of' the cylinder, said cylinder having ports loading from points thcrriu lochtcd ut prcde- 4150 ter-mined distances l'rom thc ends ihcrcof to the chambers of ille valve casing and controlled by thc piston to alter'- nutcly a'dniit and exhaust iluid pressure through thc cylindcr lo salti chambers to rccli'irocate the valve.

ifi. in :i iluld pressure operated iool, thc combination ivih a cylinder. of u reciprocating piston therein, u handle 'comprising :r supporting sleeve engaging and relatively rnovubhl with respect to the cylinder', said cylinder having an exhaust port icudinar t'rom bnc cnd thereofhnd controlled by said handle. :rnd fluid pressure actuated melius tendini,r to rclatlvcly lnovc said handle und cylinder so as t opcnsaid exhaust port.

comprising a cylinder xed to said handle 4and aplungcr therein interposed between said cylinder and handle and movable relatively' to said handle, said plunger cylinder being in constant communication with thefluid pressure supply.

15. In a fluid pressure operated tool, the combination with a cylinder, of a reciprocating piston therein, av'alve casing having supply and exhaust ports leading to the opposite ends of thc cylinder, a piston valve in said casing controlling the ports therethrough, a handle comprising a sleeve mounted on said cylindei` and longitudinally movable with respect thereto, said cylinder having an exhaust port leading from the front ends by said handle when the latter occupies a given position relative to the cylinder thereby opening said exhaust port, and Iiuid pressure actuated means tending to relatively move said cylinder and handle in opposite directions.V

16. In a fluid pressure operated tool, the combination with a cylinder, of a reciprocating piston therein, a valve casing having supply and exhaust ports and ports communicating,r with the opposite ends `of the cylinder, a piston valve in said easing controlling the ports therethrough, said cylinder having ports controlled by the piston leading from points in the cylinder further from the ends thereof than the length of the piston and passages thereof and controlled leading from said ports to the ends of the valve casing for alternately admitting and exhausting duidy pressure through the cylinder to reciprocate the valve and thereby reverse the strokeof the piston haust port the end of the cylinder through which fluid pressure has owed to the valve casing, yand means'for. preventing the movement of the valve during. the communication ror the valve casing with the exhausting end of the cyli'rder.`

17` In a fluid pressure operated tool, the combination with a cylinder, of a reciprocating piston therein, casing having supply and exhaust portsand ports communcating with the opposite ends of the cylinder, a piston valve in said casing controlling the ports. therethrough, said cylinder having ports controlled by the plston leading to theends of the valve -casing for alternately admitting and exhausting uid pressure reciprocate the valve and thereby rev'ersethe stroke of the piston by connecting with the exhaust port cylinder through which iiuid pressure has owed to the valve casing, and means for admitting fluid pressure to the end of the valve casing during its communication with the exhausting end of the cylinder tolprevent movement of the valve.

A In testimony whereof, I sign this specification in the presence of two witnesses.

CHARLES H. JOHNSON.

Witnesses Giro. L. WILKINSON, C. C. CUNNINGHAM.

by connecting with the ex'.-

a valve through the cylinder to' the end of the. 

